Apple's announcement of a 64-bit Power Mac G5 triggered a tsunami of hype, and you can expect another if, as expected, Advanced Micro Devices releases an Athlon 64 chip in September.

To understand why the number of bits is important, but why it might not necessarily be the only important consideration in desktop computing speed, start with four 640-pound piles of horse manure. The application here is to move the manure into a truck and drive it to the compost heap 10 miles away, where it will be used by gardeners and speechwriters.

To do this application, we have four ``processors'' with shovels. Gus has a shovel that holds 8 pounds, Gertrude's shovel holds 16 pounds, Morgan's holds 32 pounds and Arnold wields a whopping 64-pounder. Industrious folk, they shovel once each second.

Elementary math says it will take Gus 80 seconds, Gertrude 40 seconds, Morgan 20 seconds and Arnold just 10 to process their identical mounds of manure.

Ah, but there's more to the task of manure and data than shoveling. Gus is a former New York City cab driver and barrels his truck along at 2 miles a minute, reaching his destination in 5 minutes for a time-to-completion of 6 minutes, 20 seconds.

His friend Gertrude is law abiding and drives at a mile a minute. Her time-to-completion is 10 minutes and 40 seconds, even though she ``processed'' twice as fast as Gus. Morgan and Arnold go nose-to-nose at a mile-and-a-half a minute, arriving after 6 minutes 42 seconds, for a time-to-complete of 7 minutes and 2 seconds and 6 minutes and 52 seconds.

And the point of the story (beyond the one that using a manure analogy is certain to draw all sorts of e-mail I wouldn't show my mother)?

The point is that processor speed is but one measure of a desktop computer's performance. The speed at which data moves across the system to input-output devices, and the speed of the devices themselves greatly affect the perceived speed. The wide differences between components in the Gus et al analogy won't be found in real life, but there are differences and they do affect performance.

Another point is that few of us ordinarily do tasks that require that much computing power, and on a practical level, the 20-year debate over who offers the hottest desktop is going to be for the titillation of techies and giving the marketing folk some sizzle.

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Questions and comments are welcome. Send them to Larry Blasko, The Associated Press, 50 Rockefeller Plaza, New York, NY 10020-1666. Or e-mail lblasko(at)ap.org.